VALEURRENVOYÉE

On success the generated key_t value is returned. On failure -1 is
returned, with errno indicating the error as for the stat(2) system
call.

CONFORMITÉÀ

POSIX.1-2001.

NOTES

Avec les bibliothèques libc4 et libc5 (et également sous SunOS 4.x), le
prototype était
key_tftok(char*pathname,charproj_id);
Today proj_id is an int, but still only 8 bits are used. Typical usage
has an ASCII character proj_id, that is why the behavior is said to be
undefined when proj_id is zero.
Of course no guarantee can be given that the resulting key_t is unique.
Typically, a best effort attempt combines the given proj_id byte, the
lower 16 bits of the i-node number, and the lower 8 bits of the device
number into a 32-bit result. Collisions may easily happen, for example
between files on /dev/hda1 and files on /dev/sda1.